1. Field
Apparatuses and methods consistent with exemplary embodiments relate to interpolating an image, and more particularly, to interpolating between pixel values of integer pixel units.
2. Description of the Related Art
In a related art image encoding and decoding method, one picture is divided into a plurality of macro blocks so as to encode an image. Then, each of the plurality of macro blocks is prediction-encoded by performing inter prediction or intra prediction thereon.
Inter prediction is a method of compressing an image by removing a temporal redundancy between pictures. A representative example of inter prediction is motion-estimation encoding. In motion-estimation encoding, each block of a current picture is predicted by using at least one reference picture. A reference block that is the most similar to a current block is searched for in a predetermined search range by using a predetermined evaluation function.
The current block is predicted based on the reference block, a residual block is obtained by subtracting a predicted block, which is the result of predicting, from the current block, and then the residual block is encoded. In this case, in order to precisely predict the current block, sub pixels that are smaller than integer pixel units are generated by performing interpolation in a search range of the reference picture, and inter prediction is performed based on the sub pixels.